L40, the monolithic, geometrical building on Rosa-Luxemburg-Platz in Berlin-Mitte is a collaborative project designed by Bundschuh Architekten and Cosima von Bonin. This sombre, striking and instantly-recognisable structure was commissioned by Verein zur Förderung der Kunst und Kultur am Rosa-Luxemburg-Platz e.V. and the building was competed in January 2010.
Constructed entirely in concrete, the building comprises a number of luxurious loft and duplex apartments as well as commercial units characterised by panoramic, floor-to-ceiling windows and elongated rooms. The stark, raw façade of L40 is juxtaposed with the overwhelmingly-light interiors and incorporates a sustainable, foam-glass insulation.